Just before my junior year of high school, as the last precious days of summer vacation shrank away, my mom sat me down for a serious conversation. She calmly told me that she had been diagnosed with breast cancer — a year earlier.

I must’ve looked at her as if I’d just witnessed someone get hit by a truck. She quickly explained that it had been localized stage one, which meant she hadn’t needed chemotherapy, just a small operation and seven weeks of radiation. She said she didn’t tell me because she didn’t want to worry me over something that was no big deal.

“So you’re okay now?” I’d asked, feeling more like I was the one who had been hit by a truck. She said yes, we hugged and that was that.

But I wasn’t okay. I was angry, hurt and shaken. I felt like an afterthought. I wondered if my mom thought I was this fragile child who couldn’t handle anything critical even though I was 16. What if I really was that incapable? The thought laid seeds of doubt in my brain. Even now as an adult, I can sometimes feel paralyzed by stressful situations and question my ability to get through them.

It is not uncommon for parents to keep a serious diagnosis such as cancer from their children, says Evan Imber-Black, director of the Center for Families and Health at the Ackerman Institute in New York. “I think parents often think that they need to protect their children from this knowledge, that it would be too upsetting.”

Shame can also play a major role in why a parent keeps their illness a secret, as can fear of facing the reality of the situation. For instance, Vered DeLeeuw, a recipes blogger from San Francisco, believes her father kept his Parkinson’s from his adult children for four years because he didn’t want to be pitied.

“We tried to respect his obvious wish not to talk about it,” DeLeeuw says. “But it was incredibly stressful to know that something was very wrong with a loved one and not be able to talk about it or try to offer support.”

How different cultures view illness is also a factor in family secret-keeping.

Jeanny (who preferred not to disclose her last name for privacy reasons), a leadership consultant from Sunnyvale, Calif., says, based on her experience, it’s normal in Asian cultures for parents to keep a serious illness hidden from their children. Even though Jeanny was 35, her parents refused to tell their only daughter that her mother had breast cancer until the disease was in remission a year later.

“I felt angry, robbed, betrayed, unloved, and abandoned,” Jeanny says. “Ironically, these were the common feelings I had growing up in my traditional Asian American family, in which emotional displays, connection and genuine love and care for family members is not practiced.”

While parents may think they’re protecting their children from pain by keeping them in the dark, that can actually do more harm than good — to everyone involved. Columbia University researchers studied the effects of 13,000 secrets and found keeping them often led to preoccupation, decreased trust and reduced satisfaction with life.

“When you keep an illness secret, that adds a layer of complication and confusion for [young] children,” Imber-Black says. “Because children are very good detectives, and they know when something is being kept from them.”­

When younger kids think their parents are keeping a secret, they often imagine the worst-case­ ­scenario — that a parent is dying and there’s nothing they can do about it. Even if that is the case, not trusting children with the truth breeds fear and resentment rather than love and support, which can, over time, permanently taint a parent-child relationship.

Musician and writer Adam Cole’s mother hid her multiple sclerosis from him for six years, starting when he was only 12, which left Cole making terrible assumptions about her.

“I thought my mother had a psychosomatic illness, that it was all in her head, and this unnecessarily lowered my regard for her,” says Cole.

Imber-Black says keeping an illness a secret also isolates the sick parent, creating a divide between them and their family. This was also seen in the results from a tests performed at Columbia University on secret-keepers specifically. Such isolation can lead to emotional and physical fatigue because hiding something so significant takes effort.

There is, however, a way to bridge that gap, and that starts with the sick parent deciding to have that first, tough conversation with their children.

That is easier said than done, especially if you’re dealing with preteens, who tend to blow things out of proportion, and young children, who may need everything explained simply. It’s even harder if sick parents have been withholding their diagnosis for some time already.

That’s why Imber-Black recommends seeing a family therapist who has experience working with people with illnesses. She has helped parents work up to telling their kids by having them role-play without the children there. When there are two parents, sometimes she’ll have the sick parent play the child and the healthy parent play the sick parent to help change-up perspectives. Afterward, they’ll dissect how it went and make a plan for the actual telling.

While revealing a diagnosis to adult children comes with its own set of challenges, when your children are still young enough to live at home, the diagnosis may affect many aspects of their day-to-day lives. That’s why Imber-Black stresses that it shouldn’t be thought of as a one-time event.

“It’s a process,” she says. “It’s never one telling. There needs to be at least occasional conversations about what’s happening, what’s the process, where are we in the process, and watching how much a child can take in at a given time. Then stopping and taking it up another day.”

You want to be careful not to overwhelm your kids by talking about the illness too much. It is a good thing for them to learn that their parents aren’t invincible, but it’s also important for them not to get emotionally burned out. “You want to help keep life normal in an abnormal situation. [But] stay open to children’s questions,” Imber-Black says.

Finally, while it may feel strange at first, letting your children comfort you is not only okay but encouraged.

“Sometimes parents think that should only go in one direction,” Imber-Black says. “No, It should go in both directions.”

Keeping something as life-changing as a serious illness from your children can take a major toll on you and your family. Sharing it with them, however, can only strengthen your bond and help everyone navigate the journey ahead.